The two aims of this core are (1) to provide chronically treated rodents for the projects in this Center; and (2) organize and store tissue from non-human primates as needed by the projects in this Center. Many of the projects described in this program will utilize animal models of chronic drug administration as a means of evaluating the long term consequences of chronic exposures to drugs of abuse. This Core facility will provide animals self-administering cocaine and heroin for the evaluation of various study in Projects I, IV-VI. All routine surgical preparations and training will be provided by the personnel in this Core. Projects I-IV, and VI will require animals chronically treated with novel tropane analogs synthesized in Core C. The present Core will interact considerably with Project IV which will provide in vitro and in vivo testing information regarding the most appropriate dosing, route of administration, and duration of testing of novel tropanes. All routine treatment and testing of animals will be conducted in this Core facility. Finally, Core personnel will be responsible for proper sacrifice, brain collection, and tissue storage of brains from non-human primates utilized in projects in this Center. Records will be maintained for distribution of tissue to various Projects involved in the evaluation of neurobiological markers in non-human primate tissue.